Shuttle speed monitor



Dec. 19, 1967 R. w. scHooLEY, .1R 3,358,717

SHUTTLE SPEED MONITOR Filed May 21, 1965 '2 sheets-sheet 1 Ticl. 5.22

T//WE E DEL/4V G m M L A A amm/.f

DeC- 19, 1967 R. w. SCHOOLEY, JR 3,358,717

SHUTTLE SPEED MONITOR 2 Sheeis-Sheet 2 Filed May 2l, 1965 MMM A 70m/Ey;

United States Patent 3,358,717 SHUTTLE SPEED MONITOR Robert W. Schooley, Jr., R.D. 2, Lebanon, NJ. 08833 Filed May 21, 1965, Ser. No. 457,598 Claims. (Cl. 139-341) This invention relates to the control of weaving machines and more particularly it concerns apparatus for sensing the speed of a moving shuttle and providing a stop signal when such speed drops below a prescribed magnitude.

Modern day high speed weaving involves the use of looms which operate with ilying shuttles whose velocities often reach as high as 150 feet per second. These iiying shuttles are generally of elongated configuration and are pointed at their ends. Also, these shuttles are hollow and they carry in them a spindle upon which is wound the weft or filler yarn used in weaving. When the warp yarns in the loom are in a proper position to receive a new weft or filler, a picker stick at one side of the loom slaps the shuttle and throws it across to the other side where it is caught in a shuttle box. During its travel, the shuttle plays out a length of weft yarn which is then beat up into position among the warp yarns. The warp yarns are thereafter shifted in position and a picker stick at the other side of the loom then slaps the shuttle back to the rst side for the laying out of a new weft yarn.

Since the shuttle is actually thrown across the loom upon being struck by the picker sticks, it follows a ballistic trajectory. Accordingly, if its speed at the beginning of each throw is not within precise limits, the shuttle will miss the shuttle catching arrangement on the other side of the loom. Should this happen, the loom must be stopped before the warp yarns are shifted or damage will occur to the material being woven or to the loom itself. It is important, therefore, to be able to sense the shuttle velocity with a high degree of accuracy in its early stages of ight; and to develop a control or stop signal when this detected velocity falls outside its prescribed limits.

The measurement of shuttle speeds has proven to be a ditiicult task. One reason for this is that the shuttle speeds are extremely high. Also, the traversal time of the shuttle is very short so that in order to produce a stop signal in time to be effective, the shuttle speed measurement must be completed almost immediately upon ejection of the shuttle out of its shuttle box. Such rapid and precise measurernents would appear to dictate the use of electronic type sensors. However, because of the vibratory effects experienced in and around this region of a high speed loom, it would be very difficult to obtain a high enough signal to noise ratio to produce reliable indications. These vibratory eiiects produce varying lateral displacements between the shuttle and the sensing elements on the loom; and these displacements and their variations severely affect the output of capacitance or inductive type proximity sensors. Also, the precision of timing obtainable from a variable indicator or capacitor sensing device is below that necessary for reliable monitoring of the high speeds involved. This is because the relatively moving elements associated with such devices cause a gradual, rather than a sharp or sudden change in electrical output as the parts move past each other.

In the present invention the above difficulties are eliminated by means of a photoelectric detection system arranged in a novel manner to respond to the movements of a shuttle emerging from its shuttle box. This detection system -includes a photosensitive cell capable of responding to the passage thereby of positionally displaced points along the length of the shuttle. As each point passes by the photosensitive cell, it generates a signal and applies this signal to a timing means. if the time between suc- 3,358,717 Patented Dec. 19, 1967 cessive signals is too long, as where shuttle velocity is too low, then an output will be produced in suiiicient time to stop operation of the loom. tlf, on the other hand, the signals occur in rapid enough sequence, no such stop Signal will be produced.

According to one of its features, the present invention overcomes certain disadvantages normally considered characteristic of photosensitive devices. These disadvantages lie in the fact that the sharp focusing capability of these devices, which is used to obtain sharply defined high resolution signals, also makes them quite sensitive to vibrations and lateral displacements.

In the case of a high speed loom, the associated vibrations and lateral shuttle displacements would cause the sharply focused light beam to move undesirably with respect to the photosensitive element, thus producing many false signals and preventing the proper presentation of true signals.

The present invention, in one of its aspects, overcomes these disadvantages and eliminates the above-described difficulties which would be associated with the provision of photoelectric sensing devices on a high speed loom. According to this aspect of the invention, there is provided a light source and a photosensitive element along the path of shuttle flight. However, neither the light source nor the photosensitive element is focused to a sharp beam. Instead, both elements are purposely arranged with an appreciably wide field of view.

In the illustrative embodiment of the present invention, a light source and a photosensitive element are each mounted Within a solid support block. The block is formed with openings in one side to expose the light source and sensitive element and provide each with a wide field of view; although the sensitive element is maintained shadowed from the direct rays of the light. The support block can be positioned along the path of shuttle l'light with the openings facing the shuttle as it passes by. The shuttle may be provided with small light rellective elements displaced from each other by a known distance along its outer surface. As each light retlective element passes through the beam of the light source, it will at some point reach la position such that a portion of the light beam becomes retiectively directed at the photosensitive element. As will be explained more fully hereinafter, the signal produced by the photocell will be at least as sharp as that produced when a highly focused light beam is used. Moreover, as will also be explained hereinafter, the wide field of View permitted by the light source and photosensitive element renders the device virtually insensitive to lateral displacements of the shuttle or to the vibratory eifects produced by loom operation.

According to one of its features, the present invention makes possible the reliable generation of control signals based upon changes in shuttle speed which cause microsecond variations in the displacement of successive signals from the photosensitive element. In its illustrative embodiment, the present invention makes use of a bistable or binary circuit which is switched between alternate states upon the occurrence of successive outputs from the photosensitive element. During the time after the binary circuit is rst switched, it initiates operation of a ramp voltage generator Whose output is supplied to a firing device set to tire lat a given threshold voltage. If the shuttle velocity is acceptably high its second light reiiective element will cause the photosensitive element to switch the binary circuit and stop operation of the ramp voltage generator prior to the occurrence of the threshold voltage. If, on the other hand, the shuttle velocity is too low, the binary circuit will not be switched until after the threshhold voltage is reached. In such case, the firing device will lire and a signal generated thereby which can be used to stopoperation. of the loom before serious damage occurs.

There has thus been outlined rather broadly the more important features of the invention in order that the detailed` description thereof that follows may be better understood, and in Iorder that the present contribution to the art may be better appreciated. There are, of course, additional features of the invention that will be described hereinafter and which will form the subject of the claims appended hereto. Those skilled in the art will appreciate that the conception upon which this disclosure is based may readily be utilized as a basis for the designing of other structures for carrying out the several purposes of the invention. It is important, therefore, that the claims be regarded as including such equivalent constructions as do not depart from. the spirit and scope of the invention.

Specific embodiments of the invention have been chosen for purposes of illustration and description, and are shown in the accompanying drawings, forming a part of the specication, wherein:

FIG. 1 is a schematic block diagram illustrating a shuttle speedY monitoring system according tothe present invention;

FIG. 2 is an enlarged view, partiallyl in section and illustrating certain details of a shuttle, a shuttle box and a sensing head forming aportionof the system of FIG. l;

FIG. 3 is a view taken along line 3-3 of FIG. 2; and

FIG. 4 is a schematic circuit diagram of the electrical portions of the system of FIG. l.

In FIG. 1 a loom is schematically represented by a dotted line box 10. ShuttleboxeslZ and 14 are provided on each side of the loom. Each of these shuttle boxes is constructed to accommodate a shuttle16 which travels in free ight therebetween, to lay out a weft or ller strand in a manner well known in the weaving art. 'lhe shuttle is impelled across the` loom by means of pivotally mounted picker sticks |18 and 204 arranged to swing rapidly toward their associated shuttleboxes 12 and 14. and to strike the shuttle nested therein. The impact of the picker stick throws the shuttle across the loom` toward the opposite shuttle box` whereit is caught and maintained until theloomcycles to-a pointrwhere the opposite picker stick strikes the other end of the shuttle sending it back to be caught in the rst shuttle box.

The shuttle 16 itself, as shown in FIGS. 2 and 3 is of elongated configuration and is provided with pointed ends. The central portion of the shuttle ishollow. and is made of wood, plastic or leather; while its pointed ends are made of steel. Within the centraly portion of the shuttle there is provided a thread carrying spindle 22 whichl supplies the weft or filler yarns used in weaving.

The shuttle boxes 12 and 14 are designed to hold the shuttle in proper position and alignmentso that itvwill be correctly aimed to follow a predetermined trajectory when struck by the picker sticks 18 and 20. Theshuttle boxes are often lined with leather for thismaterial4 has been found to possess the bestcombination of. friction, yield-ability and resilience necessaryto both thelcatching and guiding Iof the shuttle at each end ofitsflightfpath.

It will be appreciatedtthat the initialy Velocity of the shuttlehas an important effect on the path of its ights across the loom. It has, in fact, been discovered' that by knowing the shuttle velocity'immediately after it has left one shuttle box, one can predict whether vor notthe shuttle possesses suflicient momentum to carry itto a point where it will be caught in the opposite shuttle box. The ability to predict shuttle destination in its early stages of flight is particularly important in the case of high speed weaving looms for such looms require a certain amount of time to stop theirV operation and the earlier that a stop signal can be generated, the less likelihoodthere will be that the loom will cycle with its shuttle and weft or ller yarn improperly positioned. Should the loom continue operation under sucht. conditions, damage wouldoccur either to the fabric being woven, or to the loom itself, or to both.

As shown in FIGS. l and ,2, there is mounted immediately beyond each shuttle box a photoelectric sensing head, indicated generally at 24 and 26. The sensing heads, which will be described in greater detail hereinafter, are positioned along the initial portions of the shuttle ight path with their sensitive sides facing in the direction of the passing shuttle. The shuttle 16 itself has a generally nonreflective outer surface along which is provided two highly retlective strips, 28 and 30, displaced from one another by a given amount. As each strip passes by a sensing head 24 or 26, it causes the sensing head to produce an electrical pulse signal which is communicated along a line 32 to an amplilier 34. This pulse signal is strengthened in the amplifier 34 and then transmitted through a gate circuit 36 to a binary or bistable switching circuit 3S. The binary circuit 38 is capable of. producing a continuous output voltage whose magnitude switches suddenly between a higher and a lower level upon each occurrence of an input pulse signal from the amplifier 34. The binary output is connected to a ramp Voltage generator 40 which, in response to sudden changes in input voltage, produces a gradual change in output voltage. The output 'of the ramp generator is connected to an alarm signal generating circuit 42 which is set to respond to a predetermined voltage level. The signal output from the alarm signal generating circuit is supplied via a line 43 to the loom 1&3*` for automaticallyv terminating operation .of the loom when the alarm is activated.

Inoperation of the system, a picker stick 18 strikes the shuttle 16 causing itto beA ejected from its associated shuttle box 12 and to` be thrown across the loom toward the opposite shuttle box 14. As the two reflective strips 28 and 30 on the shuttle surface passby the sensing head 24, a pair of electrical pulse signals are generatedand trans- -mitted over the line 32 to the amplier 34. TheseV pulse signals will be -displaced in timeA by ank amount inversely proportioned to the shuttle flight velocity.

The first amplified pulse signal causes the bistable switching circuit 38 to switch suddenly to a higher magnitude output voltage. This in turn causes the ramp voltage generator 40 toproduce a gradually increasing voltage which rises toward thethreshhold or tiring voltage level tol whichthealarm circuit 42 is set.

The second amplified signal produced by the passage ofthe second reflective strip 30 over the sensing head 24, alsoA passes through the gate circuitl 36 to thel bistable switching circuit 38 and causes it to switch` suddenly to a lower magnitude voltage output. This immediately causes the ramp generator 40 ,toV initiate a gradual decrease in itsy output voltage.

The waveforms shown at` the outputs of the various components in FIG. 1 are helpful in understanding th@ operation of the system. As shown at the output of the amplier 34, there are, produced two signal pulses= aand b, at the instants that the reflective strips 28 and 30 pass by the'sensing-head` 24. The position of thesolid line signal pulse` b indicates a time displacementvwhich occurs when the shuttle velocity is susceptibly high. The position of the dotted line signal pulse,'on the other hand, indicates a time displacement which would occur if the shuttle velocity were too low.

The signal pulses when applied to the bistablerswitching circuit 38, cause its output voltagernagnitudes to switch as shown in the waveform. That is, the rst signal pulse a, causes a sudden rise inthe magnitude of output voltage of the bistable circuit; and this voltage is maintained until the occurrence lof the subsequent pulse b. As indicated, this higher voltage output is maintained over a longer duration where the shuttle velocity is low. The voltage output from theramp generator 40, begins to rise at a predetermined gradual rate immediately upon the switch,- in g` of the bistable circuit 38. T he gradually rising voltage, as shown, approaches a thresholdvoltage level'c, which is the voltage to which the alarm 42 is set to respond. If, as shown in the solid line waveform, the voltage input from the bistable circuit 38 suddenly drop as shown, shuttle speed is acceptably high, the ramp generator voltage will not yreach the threshold voltage level c, but will immediately begin to descend. If, on the other hand, the shuttle speed is too low, then, as shown in the dotted line extension of the Waveform, the continued high voltage input from the bistable circuit 38 will maintain the rising ramp generator voltage so that it will exceed the threshhold voltage level c and will cause the alarm 42 to fire.

The second sensing head 26 is mounted with respect to its associated shuttle box 14 in precisely the same manner as in the first sensing head 24. The second sensing head 26 is also connected via the line 32 to the amplifier 34 and other electrical components, so that shuttle speed going from shuttle box 14 to shuttle box 12 will be monitored in precisely the same manner as described above with the sole exception that in this latter case, the second reflective strip 30 will pass the sensing head 26 first to cause the occurrence of the first signal pulse a.

Because of the fact that both sensing heads 24 and 26 are connected to the same electrical elements, the heads will each also produce signals when the shuttle 16 goes into their associated shuttle boxes at the end of its journeys. Inasmuch as shuttle speed at the end of each journey is considerably slower than the beginning, it would be likely, but for the arrangement herein for a false indication of insufficient shuttle velocity to be produced, with consequent unnecessary and troublesome stoppage of the loom.

According to the present arrangement there is provided a time delay device 44, connected to receive signals from the binary switching circuit 38 and to control the gate circuit 36. The time delay device is set to respond only to the negatively going output voltages of the binary switching circuit 38, so that it is affected only after the occurrence of the second in each pair of pulses from the sensing heads 24 and 26. The time delay responds by immediately applying an inhibit signal to the gate circuit 36 which causes the gate circuit to prevent further passage of pulse signals to the binary circuit 38. Then after a preset time, the time delay device 44 removes this inhibiting signal. This preset time is set to exceed the duration of shuttle Hight, but to terminate prior to the subsequent ejection of the shuttle from the other shuttle box. The time delay is of course dependent upon the particular loom involved and can be set accordingly.

FIGS. 2 and 3 illustrate in greaer detail the construction of the sensing heads 24 and 26. As shown in FIG. 2, the sensing head 24 is positioned immediately `beyond its associated shuttle box 12 along the trajectory or path of Hight of the shuttle 16 as it leaves the shuttle box 12. The sensing head 24 comprises a support member 50 formed of a solid block of material such as plastic. The support member 50 is bored at 52 and 54 along two axes which converge at a point just beyond a surface 55 facing the shuttle Hight path.

A small electric lamp or similar source of light `capable of providing illumination over a relatively wide sector is provided with the first bore 52. An example of such a lamp is the GE type 253X lamp which is used in pen light type flash lights. The lamp 56 is positioned in the bore 52 at a point close to the outer surface 55 of the support member Si), so that it will project a beam of light of generally conical shape out across the Hight path of the shuttle 16.

A photosensitive cell 58 is mounted Within the other Ibore 54 also at a point close to the surface 55 of the support member 50 so that it possesses a field of view which substantially overlaps the conical beam from the lamp 56 in the region of the shuttle Hight path. The photosensitive cell may be a photovoltaic cell such as the wafer shaped Silicon Solar Cell made by International Rectifier 6 Corporation. The cell 58 and the lamp 56 are, of course, located deeply enough within the bores 52 and 54 of the support member 50 so that the cell 58 is shielded or shadowed from direct illumination by the lamp 56.

As shown by the dotted outline of the shuttle in Hight passing by the sensing head 24, it will be seen that the support member 50 is mounted with its surface 55 located approximately one-eighth to three-eighths of an inch away from the surface of the passing shuttle 16. Because of the vibratory effects and other factors influencing shuttle Hight and support member position, the shuttle lateral position relative to the surface of the support member 50 may vary as much as plus or minus one-eighth of an inch. The above described construction of the sensing head 24 however accommodates this variation and yet enables the production of very sharply defined signal pulses which are precisely timed in conjunction with shuttle passage.

The reflective strips 28 and 30, which are displaced along the length of the shuttle 16, may simply be metal staples or other elements having a highly reflective surface. These elements should, of course, be relatively small in or-der to ensure a sharply defined and precisely timed output signal. As stated above, the lamp 56 provides a rather wide field of illumination while the photosensitive cell 58 itself has a wide field of vision. As stated above, these fields of illumination and vision overlap each other to a great extent. This situation however does not adversely affect the sharpness of the reflected signal from the shuttle; and, in fact it provides the device with an ability to accommodate lateral shuttle displacements. The reason for this is that the cell 58 will respond only to that portion of the rays of the lamp 56 which actually reHect off the strips 28 and 30 in a direction such as to fall upon the cell 58. For any given lateral displacement of the shuttle surface from the lamp 56 and the cell 58, there is only one position of the reflective strips which will redirect any of the rays from the lamp back toward the cell. Thus, the Wide fields of coverage of the lamp 56 and the cell 58 makes no difference whatever on the precision of timing of the photoelectrically produced signal. Also, because of the fact that the lamp and cell have wide and overlapping fields of illumination and view, it is possible for the above described reflection phenomenon to occur at any lateral displacement of the reflective strips 28 and 30 from the surface 55 of the sensing head 24. If, however, the beam from the lamp 56 were focused along a very sharp line, then the cell 58 would receive reflected light from the strips 28 or 30 only when the shuttle 16 was displaced by single certain amount from the support member 50. Thus with the arrangement of the present invention, it is possible to obtain sharp and accurate signals irrespective of lateral shuttle displacements from the sensing head.

The circuit diagram of FIG. 4 illustrates the various circuit components used in practicing the invention. As mentioned previously, the photocells 58 are electrically connected via a common input line 32 to the amplifier 34. Tln's amplifier as shown in FIG. 4, includes a double triode tube 60 which provides two stages of amplification. The output of the tube 60 is coupled via a capacitor 62 to one grid of another double triode 64 connected to form a Schmitt trigger circuit. Such circuits are well known devices for producing very sharply defined voltage impulses in response to relatively weak input signals. The output from the Schmitt trigger circuit is taken from the plate of the second stage thereof and is coupled through a capacitor 66 and a gating diode 68 to the binary switching circuit 38. The binary switching circuit itself is formed of a double triode 70 having its plates and grids cross coupled -by means of parallel connected resistorcapacitor circuits 72 and 74.

When the binary switching circuit 38 receives its first impulse (pulse a in the waveform shown in FIG. l), the left side of the double triode 70 conducts and such conduction causes the right side of the triode to cease conduction. Consequently, the plate of the right side of the triode immediately rises to supply potential where it remains until a subsequently applied pulse reverses the conduction to the right side of the triode. This right side plate is connected to the input of the ramp generator 40 to cause it to produce the gradually increasing output voltage as described above.

Th ramp generator 48 simply comprises a resistor 76 and a capacitor 78 connected in series with each other between the plate of the right side of the triode 70 and ground. When the plate of the right side suddenly rises to supply potenial as described above, current passes through the resistor 76 and into the capacitor 78. The voltage across the capacitor 78 then begins to rise gradually, the rate of rise being a function of the relative sizes of the resistor 76 and the capacitor 78.

The voltage across the capacitor 78 is applied to the grid of a gas tube such as a thyratron 80. The thyratron is arranged to llire, or go into self-sustaining conduction when its grid potential achieves a certain predetermined magnitude. It will be seen that if a second pulse is applied to the binary switching circuit prior to the voltage across the capacitor 78 achieving such predetermined magnitude then the binary switching circuit will remove its high voltage supply to the capacitor 78 Which inl turn will begin to discharge and lose its potential. Thus the thyratron 80 will not lire. If, on the other hand, no such second pulse does occur until after the; thyratron does fire, then the pulse is incapable of affecting the thyratron for its operation is thenself-sustaining.

The plate circuit of the thyratron 80 is connected in series with a relay 82 between a high voltage supply and ground potential. The relay contacts may be arranged to close or opencircuits to soundv an alarm, to record a failure and, of course, to stop loom operation. A normally closed reset switch 84 is also provided in the thyratron plate circuit to terminate thyratron operation after an alarm signal has been noted, so that the loom may again be put back into operation.

The gate diode 68 is connected, via a line 86 to the plate circuit of the right side of a double triode 88 connected to form a monostable multivibrator constituting the timing delay circuit 44. The grid of the leftn side ofthe triode 88V is connected via a diode 92 and a capacitor 94, to the plate of the leftside of the triode 70 in the binary switching circuit 38. This last mentioned rplate experiences a-sudden rise in potential upon the occurrence of the second in each group of input pulses. The capacitor 94 ensures that only sudden voltagel changes are applied to the left grid' of the triode 88, and the diode 92 ensures that only positively going changes will be applied to this triode. Thus thesecond'` in each group of inputy pulses is elective to changey the grid potential on the left sideof the multivibrator. In responseto this, the' lefty side of the triode-*88 begins to conductwhile the normally conducting-right side, ceases,y to conduct. As a consequence, the right plate-potential of the triode 88 rises to supply level. Since this potential is communicated to the gate diode 68 via a line 86,- the diode is rendered incapable of passing input signals to the binary switching circuit 38'wl1i1e this situation exists. The monostable multivibrator however is arranged to revert to its naturalr state after time determined by adjustment of the resistance-capacitance cross coupling its left platey and right grid. These valuesr are set to produce a time delay which exceeds the time necessary for the shuttle to passy the sensing head which is located near the end of its particular ight path but which terminates prior to the beginning of the shuttles return flight. In this manner, the system can be rendered unresponsive to the effects producted by the shuttle as it passes by the sensing -head located at the end of each flight; yet, the system will respond to the eects produced on that sensing head as the shuttle begins its return flight.

A power supply circuit 98 is provided to convert conventional alternating current toy direct current at high voltages for supplyingl the platel circuits; of the various tubes and for maintaining continuous bias, lampandheater voltages in the system. The power supply includes an input transformer 188 having a first secondary 102 for supplying low voltage alternating current to the lamps and heaters'. A second secondary Winding 184 is centertapped to ground potentials and is connected through a pair of diodes 106 forming a full Wave rectifier to a pi type litter 108. The fitter output is a high steady voltage which is supplied via `a line 118 to the plate circuits of each of the various triodes.

It will, of course, be understood by those skillled in the art that the term light is used herein in its broadest sense; that is, in the sense of illumination with radiant energy, including, but not limited to, visible light, infra red light and ultra-violet light.

Having thus described my invention with particular reference to the preferred form thereof, it will be obvious to those skilled in the art to which the invention pertains, after understanding my invention, that various changes and modifications may be made therein without departingy from the spirit and scope of my invention, as defined by the claims appended thereto.

What is claimed as new and desired to be secured by Letters Patent is:

1. Apparatus for indicating the speed of a flying shuttle comprising, a photoelectric sensing device adapted to be positioned along a shuttles flight path, said photoelectric sensing device including illuminating means and photoresponsive means arranged such that rst and second uctuations in the light energy incident upon said photoresponsive means are produced upon the passage of a shuttle thereby, the time displacement of said fluctuations being inversely proportional to the speed of such shuttle, a ramp generator'operable to `generate an output signal whose magnitude changes gradually at controlled rates and alternately in opposite directions as successive input signals are applied thereto, means arranged to supply input signals to said ramp generator in response to liuctuations in light energy incident upon said photoresponsive means, and a signal responsive alarm means set to operate in response to an applied signal of predetermined magnitude, said alarm means being connected to receive input signals from said ramp generator.

2. Apparatus for indicating the speed of a ying shuttle comprising, a photoelectric sensing device adapted' to be positioned along the shuttles ght path, Said photoelectric sensing device including illuminating means and photoresponsive means arranged such that first and second fluctuations in the light energy incident upon said photoresponsive means are produced upon the passage of Ia shuttle thereby, the timedisplacement of said fluctuations being inversely proportional to the speed of such shuttle, amplifier meansv Iconnected to said photoresponsive means for generating voltage impulses in response tothe outputs ofy said photoresponsive means, a binary switching circuit capable of producing a continuous output signal which switches suddenly between higher and lower magnitude levels in response to .successive input signals, said binary switching circuit being connected to receive input signals'ffrom said amplifier means, a ramp signal generator operable to produce a controlled gradual change in output signal magnitude which follows rapid changes in input signals, said` ramp generator being connected to receive inputsA from said binary switching circuit, anda signal responsive alarm.means set to operate in response toan applied signal of predetermined magnitude, said alarm being connectedto receive input signals from said ramp generator.

3. Apparatus for indicating the speed of a flying shuttle which-is thrown alternately back and forth across a loom, said apparatus comprising, a pair of photoelectric sensing devices adapted to be positioned at opposite ends respectively of a flying shuttles ight path, each said photoelectric sensing device including illuminating means and photoresponsive. means, arranged suchv that irst and secfaz-358,717

ond iluctua'tions in the light energy incident upon said photoresponsive means are produced upon the passage of a shuttle thereby, the time displacement of said fluctuations being inversely proportional to the speed of said shuttle, ramp generating means operable to generate an output signal whose magnitude changes gradually at controlled rates and alternately in opposite directions as successive input signals are applied thereto, means arranged to supply input signals to said ramp generating means in response to fluctuations in light energy incident upon each of said photoresponsive means, a signal responsive alarm means set to operate in response to an applied signal of predetermined magnitude, said alarm means being connected to receive input voltages from said ramp generator, a gate circuit interposed between said photoelectric sensing device and said ramp generator, `a time delay device connected to respond to each second iluctuation in light energy occurring at each photoelectric sensing device to produce and apply to said gate circuit for a given length of time an inhibit signal which prevents signals (from passing through to said ramp generating means.

4. In combination with a loom having a shuttle which moves rapidly from one side to the other thereof, a shuttle speed monitoring arrangement comprising, a photoelectric sensing device positioned on said loom in close proximity to and facing the path of movement of said shuttle, said photoelectric sensing device including illuminating means and photoresponsive means arranged such that rst and second fluctuations in the light energy incident upon said photoresponsive means are produced upon the passage of a shuttle thereby, the time displacement of said lluctuations being inversely proportional to the speed of said shuttle, ramp generating means operable to generate an output signal whose magnitude changes gradually at controlled rates and alternately in opposite directions as successive input signals are applied thereto, means arranged to supply input signals to said ramp generating means in response to fluctuations in light energy incident upon said photoresponsive means, a signal producing circuit set to operate in response to an applied input signal of predetermined magnitude, said signal producing circuit being connected to receive input signals from said ramp generating means, and means connecting the output of said signal producing circuit in a manner such that operation of said loom is terminated upon the production of a signal from said circuit.

5. In combination with a loom across which a shuttle moves back and forth at high velocity along a single flight path extending between two shuttle boxes, the combination of a pair of photoelectric sensing devices mounted in close proximity to said flight path and near each of said shuttle boxes respectively, each said photoelectric sensing device including illuminating means and photoresponsive means arranged such that first and second iluctuations in the light energy incident upon said photoresponsive means are produced upon the passage of the shuttle thereby, the time displacement of said fluctuations being inversely proportional to the speed of said shuttle, ramp generating means operable to generate an output signal whose magnitude changes gradually at controlled rates and alternately in opposite directions as successive input signals are applied thereto, means including a signal inhibiting circuit, arranged to supply input signals to said ramp generating means in response to fluctuations in light energy incident upon any of said photoresponsive means, a signal responsive output signal producing device set to operate in response to an applied signal of predetermined magnitude, said output signal producing device being connected to receive input signals from said ramp generating means, means connecting said output signal means in a manner permitting same to terminate loom operation upon the production of a signal thereby and a timing circuit connected t-o respond to each second lluctuation in the light energy incident upon any of said photoresponsive means and operative to apply for a given length of time an in- 10 hibit signal to said inhibiting circuit to prevent the passage of signals from said photoelectric sensing devices to said ramp generating means.

6. Apparatus for indicating the speed of a ilying shuttle comprising, a light source and a photoresponsive cell mounted in relationship to each other such that each can be exposed to and located on the same side of a shuttles flight path with said photocell shaded from the direct illumination of said light source but responsive to first and second changes in reflected rays from said light source caused by displaced points on a shuttle passing thereby, the time displacement between said rst and second changes being inversely proportional to the speed of said shuttle, a ramp generating means operable to generate an output signal Whose magnitude changes gradually at controlled rates and alternately in opposite directions as successive input signals are applied thereto, means arranged to supply input signals to said ramp generating means in response to fluctuations in light energy incident upon said photoresponsive means, and a signal responsive alarm set to operate in response to an applied signal of predetermined magnitude, said alarm being connected to receive input signals from said ramp generator.

7. In combination with a weaving loom across which a shuttle moves rapidly back and forth along a predetermined ilight path between shuttle boxes located on op posite sides of the loom, a shuttle velocity measuring arrangement comprising a light source and a photoresponsive cell, means mounting said light source to radiate from a point on one side of said shuttle flight path close to one of said shuttle boxes out 4over a sector which crosses said flight path, said photocell being mounted with a eld of view overlapping said sector in the region of said flight path, said photocell also being shaded from direct illumination of said light source but responsive to changes in reflected rays from said light source caused by reflection from said shuttle, first and second light reilective strips located at displaced points along the surface of said shuttle for redirecting light from said source to said photocell to produce output signals displaced in time by an amount inversely proportional to the velocity of said shuttle, a ramp generating means operative to generate an output signal whose magnitude changes gradually at controlled rates and alternately in opposite directions as successive input signals are applied thereto, means arranged to supply input signals to said ramp generating means in response to outputs from said photocell, a signal responsive signal generating circuit set to operate in response to an applied signal of predetermined magnitude, said circuit being connected to receive input signals from said ramp generating means, and means for applying outputs from said signal generating circuit in a manner to cause termination of loom operation thereby.

8. In combination with a weaving loom across which a shuttle moves back and forth at high velocity along a predetermined llight path, the combination comprising a light source and a photoresponsive cell mounted in close proximity to each other on the same side of the llight path of the shuttle on said loom with the photocell shaded from the direct illumination of said light source but responsive to lirst and second changes in reflected rays from said light source caused by reflection from displaced points along said shuttle as it passes thereby, a ramp generating means operable to generate an output signal Whose magnitude changes gradually at controlled rates and alternately in `opposite directions as successive input signals are applied thereto, means arranged to supply input signals to said ramp generating means in response to outputs from said photocell, and a signal responsive output signal generating circuit set to operate in response to an applied signal of predetermined magnitude, means connecting said output signal generating circuit to receive input signals `from said ramp generating means, and means connecting its output to cause termination of operation of said loom.

9. A photoresponsive sensing device comprising a solid support member, a light source mounted to radiate from a point within said support member out through one side thereof to illuminate a given sector, a photoelectric cell also mounted within said support member and facing out through said one side and having a field of view overlapping said given sector, said photoelectric cell being shaded from direct illumination of said light source, electric circuit means connected to activate said light source and said photoelectric cell, said electric circuit means including amplifier means connected to receive and amplify electrical impulses generated by said photoelectric cell, a binary switching circuit capable of producing continuous output voltages of higher and lower magnitudes in alternate sequence as successive impulses are applied thereto, said binary switching circuit being connected tot receive signals from said amplifier means, a ramp voltage generator including a resistor and a capacitor connected in series across the outputof said binary switching circuit, a thyratron having its grid circuit connected across said capacitor and a current responsive output means connected in the plate circuit of said thyratron.

10. A photoresponsive sensing device comprising a pair of solid support members, a light source mounted to radiate from a point within each said support member out through one side thereof to illuminate a given sector, a photoelectric cell also mounted within each said support member and facing Iout through said one side and having a field or view overlapping said given sector, each said photoelectric cell being shaded from direct illumination of its associated light source, electric circuit means connected to activate each said light source and each said photoelectric cell, said electric circuit means including a single amplifier means connected to receive and amplify electrical impulses generated by both said photoelectric cells, a binary switching circuit capable of producing continuous output voltage of higher and lower magnitudes in alternate sequence as successive impulses are applied thereto, said binary switching circuit being connected to receive signals from said amplifier means, a gate circuit interposed between said amplifier means and said binary switching circuit, said gate circuit being arranged upon energization thereof to prevent passage of signals to said binary switching circuit, a monostable multivibrator connected to be energized by changes in the output of said binary switching circuit from a higher to a lower voltage magnitude, and to remain energized for a controlled length of time thereafter, connecting said monostable vibrator to apply, when energized, energization. signals to said gate circuit, a ramp voltage generator including a resistor and a capacitor connected in series across the output of said binary switching circuit, a thyratron having its grid circuit connected across said capacitor and a current responsive output means connected in the plate circuit of said thyratron.

References Cited UNITED STATES PATENTS 2,756,782 7/1956 Applegate et a1. 139-341 3,053,139 9/1962 Lospfs 88-14 3,172,722 3/1965 Brown 324-70 3,181,573 5/1965 Stutz 139-341 3,246,143 4/1966 steels e1 al. 324-70 2,911,013 11/1959 Hows 139-273 FOREIGN PATENTS 158,837 3/1964 Russia. 168,205 9/1965 Russia.

MERVIN STEIN, Primary Examiner.

H. S. JAUDON, AssistantV Examiner. 

1. APPARATUS FOR INDICATING THE SPEED OF A FLYING SHUTTLE COMPRISING, A PHOTOELECTRIC SENSING DEVICE ADAPTED TO BE POSITIONED ALONG A SHUTTLE''S FLIGHT PATH, SAID PHOTOELECTRIC SENSING DEVICE INCLUDING ILLUMINATING MEANS AND PHOTORESPONSIVE MEANS ARRANGED SUCH THAT FIRST AND SECOND FLUCTUATIONS IN THE LIGHT ENERGY INCIDENT UPON SAID PHOTORESPONSIVE MEANS ARE PRODUCED UPON THE PASSAGE OF A SHUTTLE THEREBY, THE TIME DISPLACEMENT OF SAID FLUCTUATIONS BEING INVERSELY PROPORTIONAL TO THE SPEED OF SUCH SHUTTLE, A RAMP GENERATOR OPERABLE TO GENERATE AN OUTPUT SIGNAL WHOSE MAGNITUDE CHANGES GRADUALLY AT CONTROLLED RATES AND ALTERNATELY IN OPPOSITE DIRECTIONS AS SUCCESSIVE INPUT SIGNALS ARE APPLIED THERETO, MEANS ARRANGED TO SUPPLY INPUT SIGNALS TO SAID RAMP GENERATOR IN RESPONSE TO FLUCTUATIONS IN LIGHT ENERGY INCIDENT UPON SAID PHOTORESPONSIVE MEANS, AND A SIGNAL RESPONSIVE ALARM MEANS SET TO OPERATE IN RESPONSE TO AN APPLIED SIGNAL OF PREDETERMINED MAGNITUDE, SAID ALARM MEANS BEING CONNECTED TO RECEIVE INPUT SIGNALS FROM SAID RAMP GENERATOR. 